automotive/audiocontrol/1.0/IAudioControl.hal

/*
 * Copyright (C) 2017 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.hardware.automotive.audiocontrol@1.0;

import IAudioControlCallback;


/**
 * Interacts with the car's audio subsystem to manage audio sources and volumes
 */
interface IAudioControl {

    /**
     * Registers the required callback object so that we can be notified when the state
     * of the car's audio system changes. This call must be made when the interface is
     * initialized.
     */
    setCallback(IAudioControlCallback notificationObject)
        generates (AudioResult result);


    /**
     * Called at startup once per context to get the mapping from ContextNumber to
     * busAddress. This lets the car tell the framework to which physical output stream
     * each context should be routed.
     *
     * For every context, a valid bus number (0 - num busses-1) must be returned. If an
     * unrecognized contextNumber is encountered, then -1 shall be returned.
     *
     * Any context for which an invalid busNumber is returned must be routed to bus 0.
     */
    getBusForContext(uint32_t contextNumber)
        generates (int32_t busNumber);


    /**
     * Control the right/left balance setting of the car speakers.
     *
     * This is intended to shift the speaker volume toward the right (+) or left (-) side of
     * the car. 0.0 means "centered". +1.0 means fully right. -1.0 means fully left.
     *
     * A value outside the range -1 to 1 must be clamped by the implementation to the -1 to 1
     * range.
     */
    oneway setBalanceTowardRight(float value);


    /**
     * Control the fore/aft fade setting of the car speakers.
     *
     * This is intended to shift the speaker volume toward the front (+) or back (-) of the car.
     * 0.0 means "centered". +1.0 means fully forward. -1.0 means fully rearward.
     *
     * A value outside the range -1 to 1 must be clamped by the implementation to the -1 to 1
     * range.
     */
    oneway setFadeTowardFront(float value);
};